//鼠标移入table修改tr样式
function highlightRows(){
    let rows = document.getElementsByTagName("tr")
    for(let i=0;i<rows.length;i++){
        rows[i].onmouseover = function(){
            this.style.fontWeight = 'bold'
        }
        rows[i].onmouseout = function(){
            this.style.fontWeight = 'normal'
        }
    }
}
addLoadEvent(highlightRows)